KOYA UNIVERSITYFACULTY OF ENGINEERING

SCHOOL OF PETROLEUM AND CHEMICAL

RESERVIOR LAB

NAME OF EXPEREMENT: Porosity by Saturating MethodNAME OF STUDENT: Kamal Abdurahman

Group: B

SUPERVISED BY: Mr.Ali Kamal

Aim of Experiment:

In this test we will try to determine the porosity by using the

saturation method.

Introduction

Knowledge of the physical properties of the rock and interaction

between hydrocarbon system and the formation rock is crucial in

understanding and evaluating the performance of a given

reservoir,

porosity could be measured from the saturation method

TheoryFor any porous material (for instance cores or cuttings), porosity is defined by:

……………………………………….3-1

Where the Vs is volume of solid, Vt the total (or bulk) volume and Vp the

pore volume. Porosity can be calculated using any

combination of two of these three parameters: •

Volume of solid, • Volume of pores, • Bulk volume.

Volume of solid

Gas expansion pycnometer

We will come on this method later in the next section.

Bulk volume

1- Geometrical volume

For cylindrical cores, the total volume is generally obtained by measuring

the diameter and the length of the cylindrical sample. This method is not

applicable for pieces of cores of irregular shape.

2- Mercury pycnometer

Mercury is a non-wetting fluid with respect to air for all the rocks.

Consequently, mercury does not enter in a sample filled by air if no

pressure is applied. The mercury pycnometer method consists in

measuring the volume of mercury without and with the core immersed.

Due to safety reasons, this method is no longer used in most of

laboratories.

3- Powder pycnometer

The principle is the same as for mercury but mercury is replaced by a fine

powder. A commercial apparatus is the Geopyc from Micromeritics. The

powder is first packed in a piston using a controlled vibration and force. The

position of the piston is measured with high accuracy (Figure 3-2). Then,

the sample is introduced in the cell, keeping the same volume of powder.

The powder is packed again under the same vibrating process and the

volume of the sample is derived from the difference in position of the

piston, knowing the section of the cell.

Figure (3-2)

Pore volume

There are mainly more than one method and techniques to determine the

pore volume of cores here we will go through the most popular one which

is:

Saturation method Using

Manual saturating Method

It is defined as the ratio of the volume of fluid phase (oil, water and gas) in

a given core sample to the pore volume (porosity) of the sample. The pore

volume is derived from the mass of the sample saturated with brine and

after drying.

Objective

The objective of this test is to determine the bulk volume, grain volume,

pore volume and effective porosity of interconnected pores of a core

sample with the use of liquid saturation method, (Figure 3-3).

Principle

A fluid of known density will drive into dry vacuumed sample, and the

difference between saturated and dry sample can give us the pore volume

invated.

Apparatus of

experiment

Main Components

The manual saturator permits to perform a sequence of vacuum and

saturation cycles on plug size samples. The standard apparatus includes a

plug sized core cell, a vacuum pump, hand operated pressure pump (2,000

psi output), a saturant vacuum tank and necessary hand operated valves

and plumbing. A larger capacity cell to accommodate full size core samples

is also available.

Equipment and sample requirements

1- Caliper

2- Stopwatch

3- Vacuum pump

4- Brine

5- Core saturator

6- Analytical balance

7- Core sample

Procedure

1- Record the temperature in the laboratory.

2- Measure each dimension three times to take the average dimensions of

the core samples and record.

3- Measure the weight of the dry core sample.

4- Wait till the weight reading will stabilize, and record.

5- Put the core plug in the core cell chamber sample.

6- Turn on valve No.1 between the vacuum pump and core sample

container.

7- Close the valve No.2 between the core sample container and the brine

reservoir.

8- Turn on the vacuum pump.

9- When the vacuum pressure will be stable, wait for 2 minute and then

turn off vacuum pump.

10- Open valve No.2 to allow brine to flow to the core sample container.

11- Once the liquid level in the saturant vacuum tank takes it is stabile

level, then turn off valve No.2. and vacuum pump.

12- Start to pressurize the core chamber cell manually and slowly up to

2000 psi.

13- Monitor and keep the pressure on 2000psi till it will stabilize on this

value.

14- Waite for 5 minute.

15- Open valve. No.2 and wait for the pressure gauge to go back to Zero

pressure reading.

16- Gently take out the core sample and wipe out the liquid on the sample

surface by rolling it on a piece of paper.

17- Measure and record the weight of the saturated core sample.

18- Measure the difference and find the pore volume and Porosity.

Discussion

Q: Discuss what type of porosity you found and why?

Effective porosity measured on core samples which are dried in a

humidity oven so that clays retain one or two molecular layers of

bound water—however, this CBW tends to a minimum and is

likely not reservoir representative.

Q: Why we take the core plugging?

-We take the core plug to determined the physical properties of

the rock like (porosity ,permeability ,saturation ,capillary

pressure ,surface & interfacial tension &…..so on).

Q: What are the objectives porosity?

-To measure the volume of oil in place &gas in place,and many

other objectives.

Result of Experiment

Report the porosity value or the sample to the nearest 0.1%.

Reference

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